The present invention relates to a safety device for machine tool operators.
More particularly, it relates to a safety device which prevents injuries of a machine tool operator when his hands are in the operating zone of the machine tool and the machine tool is activated accidentally.
Devices of the above mentioned general type are known in the art. One of such devices is based on a light barrier principle and includes a light sensitive element arranged near the working zone of the machine tool and reacting to the presence of operator's hands which block the light, so that a signal is produced and supplied to the machine drive blocking unit. The device based on the light barrier principle has however the disadvantages that it reacts not only on the operator's hands in the working zone, but also on any object in the working zone including raw materials, workpieces, etc. Therefore, such devices are impractical, and many instances operators deactivate these devices to facilitate manipulations in the working zone of the machine tool.